Coast FIRE, Barista FIRE, Lean FIRE, Fat FIRE: the variants explained
By Arpit Patel
“FIRE” gets used as if it's one target, but the variants have wildly different numbers behind them. Knowing which finish line you're actually running toward changes your savings rate, your timeline, and when you're allowed to ease off.
The number underneath all of them
Every version of FIRE starts from one idea: financial independence means your investments can cover your spending indefinitely. The common shortcut is the 4% rule — if you can withdraw 4% of your portfolio in year one and adjust for inflation after that, the money has historically lasted 30+ years. Flip it around and your target is:
FIRE number = annual spending × 25
So $40,000 of annual spending implies a $1,000,000 target. The 4% figure comes from the Bengen study and the Trinity study, and it's a guideline, not a guarantee — researchers actively debate numbers from around 3.3% (more conservative, given lower expected returns) up toward 5% (with broader diversification). Treat 25× as a planning anchor, not a precise finish line. The variants below are just different ways of reaching, or partially reaching, that number.
Lean FIRE
Lean FIRE means keeping annual expenses low — often under roughly $40,000 — so the target is smaller, frequently $1,000,000 or less. It's financial independence achieved through frugality. The upside is you get there years sooner; the trade-off is a tighter long-term budget and less margin for surprises like healthcare or a bad market early in retirement.
Fat FIRE
Fat FIRE is the opposite end: retiring without cutting back, funding a comfortable or even luxurious lifestyle. With higher spending the target balloons — commonly $2.5M+ — and so does the time and savings rate required. Fat FIRE buys resilience and optionality; the cost is that the finish line is much further away.
Coast FIRE
Coast FIRE is the most misunderstood and arguably the most useful. You've hit Coast FIRE when your invested savings, left completely alone, will grow to your full FIRE number by traditional retirement age — without you adding another dollar. After that point you still need to work to cover today's bills, but you no longer need to save for retirement; compounding does the rest. The target is:
Coast number = FIRE number ÷ (1 + r)^(years to retirement)
Example: your FIRE number is $1,000,000, you're 30, you'll retire at 60, and you expect 7% real growth. Coast number = 1,000,000 ÷ (1.07)^30 ≈ $131,000. Once you've invested about $131k, you could stop retirement saving entirely and still land near $1M at 60. That's why Coast FIRE is liberating — it converts a huge lifetime goal into a single front-loaded milestone.
Barista FIRE
Barista FIRE is semi-retirement: you stop full-time work but keep part-time or lower-stress income — the name nods to a coffee-shop job taken partly for health insurance — that covers some of your expenses while your portfolio covers the rest. It sits between Coast and full FIRE: your investments aren't yet large enough to fund everything, but combined with light work they're enough to leave the career grind.
The variants side by side
| Variant | What it means | Roughly when you can stop |
|---|---|---|
| Lean FIRE | Full independence on a frugal budget | Stop working entirely (smaller number) |
| Fat FIRE | Full independence with a comfortable budget | Stop working entirely (large number) |
| Coast FIRE | Saved enough that growth alone reaches the goal | Stop saving; keep working to cover current bills |
| Barista FIRE | Portfolio plus part-time income covers life | Leave full-time work; keep light income |
Which one are you aiming for?
Work out your full FIRE number first (annual spending × 25). If hitting it outright feels distant, Coast FIRE gives you a nearer, motivating target and an early “you can ease off saving now” moment. If you want out of full-time work before the portfolio is complete, Barista FIRE is the bridge. Lean and Fat are really the same calculation with very different spending assumptions — which is the real lever.
Enter your spending, savings, and expected return to see your FIRE number and how many years it takes to reach it.
Open the FIRE Calculator →Frequently asked questions
What is the 4% rule?
It's a withdrawal guideline: take 4% of your portfolio in the first year of retirement and adjust that amount for inflation each year after. Historically that has lasted 30+ years in most scenarios, but it's a rule of thumb, not a guarantee, and researchers debate figures from about 3.3% to 5%.
Is Coast FIRE real or just a marketing term?
The math is real. If your invested balance is large enough that ordinary compound growth reaches your retirement target by your retirement age, you genuinely no longer need to save for retirement — you only need to cover current expenses. The risk is that returns or timelines differ from your assumptions, so most people keep a margin.
How is Coast FIRE calculated?
Divide your full FIRE number by (1 + expected real return) raised to the number of years until retirement. The result is how much you'd need invested today for growth alone to reach the goal.
What's the difference between Lean and Barista FIRE?
Lean FIRE is full financial independence on a low budget — no work required. Barista FIRE still relies on part-time income to cover part of your expenses, so it's semi-retirement rather than full independence.